A tool for sharpening milling bits.

Hi,

I work in the engineering department of a college where we teach milling and lathe work. (We have 12 vertical mills)

At the moment we just throw away our blunt milling cutters, which is extremely wasteful - especially as the students only tend to use the bottom 1 or 2mm of any milling cutter.

Can anyone recommend a half decent machine for sharpening 2-4 flute end mills?

I know a lot of machines only sharpen the bottom of the bits, but even this would greatly extend the life of our budget !

Thank you.

I've used one of these. Very easy to use and takes less than 60seconds to do a 4-flute cutter. If the cutters you are getting through are of a reasonable size then you should soon get your money back.

Would also be worth getting the students to make better use of the sides of the cutters rather than just the ends.

Just to be clear for Steve: that end mill sharpening module at Arc is no longer available, only the grinding wheels to fit.

How does the cost of contacting a sharpening service compare with buying a machine and doing your own?

Unless there are institutional budgeting procedures involved that seriously skew things I can't see doing your own being financially viable.

If institutional constraints make DIY viable the obvious answer is to find a Clarkson, Boxford or similar proper small T&C grinder and learn how to use it. Great advantage of such machines is that you can gnash the ends of the cutters properly and get rather more sharpening out of them. Flute grinding, with the associated change in cut diameter, is probably too confusing in the educational environment.

Sounds like you may have the volume of cutters to make learning worthwhile. However do remember that "throw away" cutters were invented for a reason.

Allegedly the Deckel clone based sharpeners have accessories that allow them to do end mills but I have my doubts as to how practical the devices are. From what I've seen the devices sold to turn these engraving cutter grinders into poor mans T&C systems tend to be touchy in set up and over reliant on operator set-up skill to make a less than robust system work.

Darex make industrial standard "poke it in the hole" sharpeners for the ends of end mills but these don't seem to be available in the UK. Various clones are patchily available but most vendors seem to be seriously confused as to whether they are selling the drill sharpener or the end-mill sharpener.

If you just need to do the ends the Howard Hall system is attractive for very little money if the students build it. Refinements are obvious to make set-up and use easier at the expense of a moderate increase in build complexity. Howard unashamedly designs for simplest build.

If you have a surface grinder the tilting devices work well within their limitations.

Clive

Edited By Clive Foster on 25/03/2023 20:25:51

Thanks Bill, I had forgotten Ketan no longer sells them though they can be had.

They also do the proper gash cut too

If the only part of the cutter being used is the bottom 1-2mm then surely for a lot of the work an insert cutter would be a better option. No sharpening, just rotate the insert or throw it away and replace it if damaged. I know this is no good for things like plunge cutting and narrow slots but an all round course should cover insert milling cutters anyway.

Martin C

Plenty of Clarkson cutter grinders on the second hand market, they will sharpen ends and sides of cutters plus do a whole lot more things.

And here is me with an American "Cutwell" cutter grinder (air floating spindle) sitting in my garage and unused for years due to a few health issues. Surely there must be a benefit in grinding your own ? In the 80s/90s there was a good amount of cutter grinding companies around some even did a collect and deliver service in and around Birmingham.

Have a look at the Acute tool grinder advertised by Eccentric Engineering of this page.

The Acute tool grinder will touch up the end of a blunt cutter but will not be able to do the gash cut and will not be able to do the side flutes.

I have a very nice clean J&S 310 tool and cutter grinder in my workshop that was sold off from a tech. college because they no longer wanted old fashioned machines.

It will sharpen anything but for real world use it would be quite labour intensive for the amount of cutters you could sharpen in a day.

That's a good point Les, it's OK in the home workshop to spend the time getting a secondhand machine upto spec and working, learning how to use it and then setting it up for the various sharpening operations. However when someone is being paid for their time and current H&S issues need to be met by the machine the sharpeners along the lines of the EMG take a lot of beating, I learnt how to use it in about 10mins and as I said less than 60 seconds to gash and finish the ends of a 4 flute cutter. So easy enough to do as the cutters are put away or once or twice a term

Edited By JasonB on 26/03/2023 10:24:21

I think with a cutting disc on the grinder it would happily grind the gash.

Maybe, but when an accountant adds up the costs, he finds very large numbers of cutters have to be resharpened to make it pay. The savings have to balance the cost of buying and installing a grinder, powering and accommodating it, and paying men to operate the thing. And if men stop work to resharpen tools, there's the cost of lost production too. In the past, even medium sized machine shops found it cheaper to outsource sharpening than to do it in-house, but it's pricey too. More recently, industry has shifted towards disposable cutters, recycled rather than resharpened. Just a guess, but the shift might also be related to the rise of coatings, which extend the life of flat-out operated cutters by about 25%. Resharpening a coated cutter converts it into an uncoated one - perhaps more trouble than it's worth.

There are many differences between small-workshop and manufacturing best practice. One of them is resharpening. What makes sense to a hobbyist could be a disaster in a production setting, and vice-versa!

I don't think disposable cutters are a good thing in the long run. Like a lot of what is done to generate quick short-term wealth, the practice isn't sustainable.

Dave

IIRC there was a chap who owned a cutter grinder and presumably had the requisite skills who would sharpen a batch in return for a donation to charity. As there seem to be a number of people in our community who do have machines maybe we could start a scheme? Several times I've provided materials or a service to people here in return for them making a donation to Medecins sans Frontieres or other appropriate charities (e.g. the DEC for the latest natural disaster).

There are probably a number of cutter grinders that could be used for sharpening the end teeth of slotting drills, or end mills.

For larger cutters Face Mills or Side and Face cutters, probably an industrial type cuttrer grindeer would be needed.

I have tidied up a few end mills on my Worden, and am sure that D A G Brown would have used his Quorn to do the similar tasks..

I have sharpend the teeth from an inserted tooth Face Milling cutter on the Worden

Probably any of the "Kit" cutter grinders could be used for smaller cutters and inserttable tooth cutters,

Although this then makes for a need to reset the teeth accurately. (A time consuming job on the large multi tooth cutters useed in industry. Not insuperable for a cutter with just a few teeth ), .

Howard

Most re-sharpening services in our area use CNC grinders which grind the cutter all over. Years ago you could stipulate just grinding the gullet which preserved the O/D to a certain degree.

I have found resharpening a coated cutter not only gives a keener edge than the as supplied condition, but it will still out last a standard HSS, size for size.

Regards

Gray,

Thanks for the replies folks.

Chris - I'm from Brum, now working in Shropshire.... small world

Martin - There are certain parts of our course that require side cutting - just not a lot of it. I completely forgot about insert mills, it just never occurred to me to have a mix of both types ! I'll look into that tomorrow.

The EMG machine looks perfect - now to find who sells them

Thanks again all

EMG does link but not as easy as it used to be.

I have used a company called ABBCO in Nottingham for many years. Always used to leave a box of cutters with them on the way up to Harrogate ME Show.

Good and reasonably priced service.

Just a happy customer, no other connection.